What is the main purpose of the `docker tag` command?

The primary purpose of the docker tag command is to create a new tag for an existing image. Tagging is an essential aspect of versioning and organizing images within Docker. When you tag an image, you essentially assign a new alias to it, which allows for easier management and retrieval of the image, particularly when working with multiple versions.

For example, if you have a Docker image with a certain identifier, tagging it with a new name or version helps in distinguishing between various stages of development or releases, such as latest or v1.0. This feature is particularly useful when you want to push images to a repository; having the proper tags means you can easily refer back to specific versions of your images later.

This functionality supports better image management workflows and helps ensure that the right version of an image is used in deployments.